Concretions are remarkable geological curiosities. They are spherical carbonate formations composed of mineral cement. Concretions are found near and far, from Western Kazakhstan to beaches in California. Usually the size of cannonballs, they form from water eroding a piece out of sedimentary rock. They almost look man-made. Many fossils of dead creatures have been found inside these strange deposits.

Several important questions regarding concretions have long puzzled scientists. What conditions cause them to form? How long do they take to grow? Why do they stop growing? Why are they so distinct from the surrounding rock or sediments?1

Interestingly, researchers discovered the speed of concretion formation to be very non-uniformitarian, “Calcite precipitation occurs several orders of magnitude more rapidly than previously recognized in concretions.”1 In Nature, Yoshida et al. stated,

All analytical data imply that the spherical concretions formed very rapidly, at least three to four orders of magnitude faster than previously estimated timescales. The values indicate that spherical concretions are preferentially grown within clay- to silt-grade marine sediments deposited in relatively deep (a few tens of metres) environments dominated by diffusive solute transport, very early in diagenesis [changes in sedimentary rock during and after rock formation].2

Saying “four orders of magnitude [10,000 times] faster than previously estimated timescales” brings these assumed long evolutionary ages down to the biblical timescale!

The results of this new study dramatically impact understanding of the rate at which concretions form. “Until now, the formation of spherical carbonate concretions was thought to take hundreds of thousands to millions of years,” co-author Koshi Yamamoto says. “However, our results show that concretions grow at a very fast rate over several months to several years.”3